A human identifying device includes a temperature sensing module, a temperature pattern recognizing module and a human body identifying module. The temperature sensing module senses temperature distribution within the target area. The temperature pattern recognizing module determines at least one matching region out of the target area based on a human-resembling temperature feature within the temperature distribution. The temperature pattern recognizing module identifies at least one matching temperature sensor that corresponds to the at least one matching region. The human body identifying module determines if distribution of the at least one matching temperature sensor resembles at least one part of a human body contour.